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Thread summary:

Green electricity: solar power systems, renewable fuel, wind energy, buy a house, mortgage.

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Old 06-22-2008, 03:44 PM
 
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Quote:
Originally Posted by Tesaje View Post
As a proof of concept, this house does get all its power from the PV panels, then stores it in the hydrogen tanks for use during non-sunny hours and even long winters of low sun. So, with adequate storage capabilities, he has shown that you can apply PV in lower light climates.

This particular application is not cost effective, but it does show that it can be done. Which is an important first step.

The current technology is not cheap or effective enough to go mainstream, but that doesn't mean that we aren't headed that way.
Quote:
Originally Posted by Noahma View Post
you guys are just not understanding what I am saying, it is good he was able to do this, but at what cost? What is the monthly cost of this equipment vs. if he was on the grid? good for him that he got off the grid, but what I am saying is

THIS TYPE OF SYSTEM WILL NOT WORK EVERYWHERE!!!

You guys are trying to treat this as an end all solution to our problems. It is not, right now the cost / payoff is WAY TOO OFF,
in a good sunny area you can place 30 panels on your roof and produce kW of power, would you pay the extra cost if you were in a shady area for the system that would produce kW power that would cost more and need more 3x5 panels? you also need to think of the costs, a kW system costs you about $45,000, in an area you do not get enough sun in you would need to bring that up quite significantly to be able to produce the same exact power that is produced on the 45,000 system. Then you need to think of space available. You need a system that is at a 20*-40* angle facing south, with no obstructions, you need to keep the shade OFF of the system during peak hours of 10AM-3PM, the panels are 3' x 5', a small house is NOT going to be able to hold all of these panels, and significant structural redesign of the roof would need to be done to handle the panels. Yards are not big enough to house all of the panels and still be usable as a backyard.

There are SOO many more variables than just cost to be considered, when the panels get smaller and produce more power per panel then it might be worth the costs and the hassle to place them up. Batteries do not stay charged indefinitely, and the costs and hazardous materials that go into making them are sort of the icing on the cake.

the 45,000 cost is ONLY for the panels and install while tying into the grid, not including the costs of batteries and switches needed to be able to charge a system, these also require a HUGE amount of space for the storage, the batteries are not your typically car battery size, they are enough to fill a room just for a few KW system.

I design homes for use with these systems every day, it is NOT practical in quite a few areas of the country.
And you are not reading the post you quoted before going off on a rant.

As a proof of concept

This particular application is not cost effective, but it does show that it can be done. Which is an important first step.

The current technology is not cheap or effective enough to go mainstream,

This person is trying to say that this is simply a concept that might lead to ways of making similar systems work. They're not saying it will work everywhere, for everyone.

It's great this guy had the money and location to do it this way. I don't have either but that doesn't mean I can't use some of the same ideas along with other methods in a different manner to approach the same goals.
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Old 06-22-2008, 03:50 PM
 
Location: Northglenn, Colorado
3,689 posts, read 9,433,278 times
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Quote:
Originally Posted by Tek_Freek View Post
And you are not reading the post you quoted before going off on a rant.

As a proof of concept

This particular application is not cost effective, but it does show that it can be done. Which is an important first step.

The current technology is not cheap or effective enough to go mainstream,

This person is trying to say that this is simply a concept that might lead to ways of making similar systems work. They're not saying it will work everywhere, for everyone.

It's great this guy had the money and location to do it this way. I don't have either but that doesn't mean I can't use some of the same ideas along with other methods in a different manner to approach the same goals.
I understand that, I was trying to emphasis that it is NOT a solution everywhere! there are some on the forums that will take this as an end all solution to energy problems when in fact it is NOT PRACTICAL YET.
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Old 06-22-2008, 03:57 PM
 
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Quote:
Originally Posted by Noahma View Post
I understand that, I was trying to emphasis that it is NOT a solution everywhere! there are some on the forums that will take this as an end all solution to energy problems when in fact it is NOT PRACTICAL YET.

Ah, got it! You really had me wondering there...
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Old 06-22-2008, 06:34 PM
 
Location: Somewhere in northern Alabama
17,747 posts, read 53,880,773 times
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Not only is it not practical everywhere, but my jaw dropped when I read the article and it claimed that a tank full of hydrogen weighs less than an empty tank. I had to double check to make sure it was a Scientific American website.

To make it real simple, if a tank of hydrogen weighed less than an empty tank, then airplanes could just store a lot of high pressure hydrogen, and not have to use power to get in the air. The person who wrote the article was so intent on gushing that reality slipped by unnoticed.
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Old 06-22-2008, 07:00 PM
 
28,139 posts, read 39,748,049 times
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Quote:
Originally Posted by harry chickpea View Post
Not only is it not practical everywhere, but my jaw dropped when I read the article and it claimed that a tank full of hydrogen weighs less than an empty tank. I had to double check to make sure it was a Scientific American website.

To make it real simple, if a tank of hydrogen weighed less than an empty tank, then airplanes could just store a lot of high pressure hydrogen, and not have to use power to get in the air. The person who wrote the article was so intent on gushing that reality slipped by unnoticed.
In case you missed it hydrogen is lighter than air, which is why it was used as a lift gas in blimps (remember the Hindenburg?) so yes, if you added enough hydrogen to an aircraft it would lift. And the tank full of hydrogen, if placed on a scale, would weigh less than one full of air.

There was no reality slipping taking place in the article.
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Old 06-23-2008, 08:31 AM
 
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Thought i'd weigh in here in that the cost is very expensive now on these eco projects but i do believe Inovation will lower it in the near future....so keep Inovating !!

I just saw Craig Venter (Founder Human Genome Project) on C-Span 2 last week and was saying that in 1990 it cost the Government 3 billion dollars and 10 years to sequence the Human Genome. Now he said it costs 3 million dollars and a fraction of the time it originally took to sequence it back then and in 5 years he said it will cost $1,000 or even less and several hours to sequence it.

So keep the faith in Inovation.
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Old 06-23-2008, 09:57 AM
 
Location: Somewhere in northern Alabama
17,747 posts, read 53,880,773 times
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Quote:
Originally Posted by Tek_Freek View Post
In case you missed it hydrogen is lighter than air, which is why it was used as a lift gas in blimps (remember the Hindenburg?) so yes, if you added enough hydrogen to an aircraft it would lift. And the tank full of hydrogen, if placed on a scale, would weigh less than one full of air.

There was no reality slipping taking place in the article.
I can't believe that you are taken in by this misconception and misquote as well.

Reviewing what I said:
Not only is it not practical everywhere, but my jaw dropped when I read the article and it claimed that a tank full of hydrogen weighs less than an empty tank. I had to double check to make sure it was a Scientific American website.

To make it real simple, if a tank of hydrogen weighed less than an empty tank, then airplanes could just store a lot of high pressure hydrogen, and not have to use power to get in the air. The person who wrote the article was so intent on gushing that reality slipped by unnoticed.
The Sciam story did NOT say that a tank of air is heavier than a tank of hydrogen. Read it again. The exact quote of the paragraph is:
"That vented hydrogen speeds at 45 miles (72 kilometers) per hour through the atmosphere on its way off the planet—one of only two gases, the other being helium, that escapes into space entirely because it is lighter than air. In fact, Strizki's quarter-inch thick propane tanks weigh less when filled with hydrogen than when depleted."
This is totally, absolutely, and entirely wrong, and even if it was an unintentional error (which I don't think is the case), the effect is so misleading that the editor should have caught it.

A depleted tank of hydrogen contains hydrogen at atmospheric pressure, more or less. If it contained air in a depleted state, and was then used to store pressurized hydrogen, it would not be a tank, but a small bomb. The only possible way for the tank to weigh more when depleted would be if the tanks were using water to displace the hydrogen, which would mean, among other things, that the tanks would rust.

Now let's get to the meat of the issue.
No substance has a negative molecular weight. A perfect vacuum would have a weight of zero, and if you added more vacuum to a tank, the contents would still have no mass. Hydrogen has a molecular weight of just over one. It is the lightest element, but it still has mass and weight.

So, if you push more hydrogen into a pressurized "quarter-inch thick propane tank" the tank and contents will weigh more, not less. How much more? Look on this website about halfway down for some weights at 800 bar (far above the 20 bar pressures safe for a propane tank):

Hydrogen for Transport

One gallon of gasoline weighs about 6 lbs, and a similar energy of hydrogen compressed at 800 bars weighs about 3 lbs or 48 oz. So, doing the math, reducing that to 800 bars to 20 bars allows the same volume to contain only 1.2 oz of hydrogen, or .3 oz/ft3. FWIW, a tank of hydrogen compressed to 20 bars DOES still weigh a little more than a tank of air at 1 bar. At 14 bars, the weights are about equal. So much for a full tank of hydrogen weighing less than an empty tank containing air.

"just outside are ten propane tanks (leftovers from the 1970s that are capable of storing 19,000 cubic feet, or 538 cubic meters, of hydrogen)" That is a HUGE amount of gas.

So, let's figure out a maximum and minimum weight of hydrogen that can be stored.
At 20 bar, .3oz X 19,000 = 5,700 oz or 356 lbs.
At 1 bar, divide that figure by 20 and get a little less than 18 lbs.
A quick glance shows that if the gas is unpressurized, the energy storage capacity of all the tanks is similar to a tankful of gasoline in a small sedan. That seems small, considering that "From November to March or so Strizki runs the stored hydrogen through the fuel cell stacks outside his garage or in his car to power his entire house—". However, twenty equivalent tanks of gasoline would comfortably run an energy efficient house for about that time, with energy left over.

Getting back to my original point, since there are ten tanks, and 356 lbs of hydrogen, a single 1,900 ft3 full tank of pressurized hydrogen weighs roughly 35 lbs. more than a depleted tank. However, something still bothers me. 1,900 ft3 is 14,250 gallons. That equates to each tank being the size tank used on propane delivery trucks. The largest residential size propane tank is labeled at 1000 gallons capacity.

Can you imagine getting zoning to approve your storing ten tank truck sized tanks of hydrogen in your back yard???

Again, I think the article may be lacking, and that the total quantity of hydrogen storage may be being measured in hydrogen at one bar, pressurized at less than twenty bar. That puts 19000 ft3 in ten tanks of roughly 100 ft3 each. Ten 750 gal residential tanks would about do that. That means we have to go back to the idea that for all the work and cost involved, the energy storage is about the same as the gasoline contained in the neighbor's small sedan parked in the driveway.

THAT is the part of the story that wasn't overtly reported. Imagine how the green lobby would react to a more complete and truthful story that concluded "You can spend half a million dollars and spend months storing hydrogen amounting to the same energy that you can buy at a gas station for less than $80." Scientific American was pandering, being less than candid, and guilty of sloppy factual editing when it approved the article.

As a chuckle, an alternate method of storing the hydrogen could be to use a gas bag. There are only a few minor problems with that. The gas would constantly leak out of the bag, the bag would have to be ten feet wide, ten feet high, and almost the length of a football field, would tend to float away, and be a tempting target for neighborhood kids. BUT - a full tank would weigh less than a depleted one.
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Old 06-23-2008, 10:35 AM
 
Location: Northglenn, Colorado
3,689 posts, read 9,433,278 times
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Quote:
Originally Posted by harry chickpea View Post

Can you imagine getting zoning to approve your storing ten tank truck sized tanks of hydrogen in your back yard???
you should see the hoops we have to jump through for months at a time to get 2" more height approved over the max. height limit set.


by the way, very informative post.
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Old 06-23-2008, 10:54 PM
f_m
 
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Quote:
Originally Posted by Noahma View Post
I understand that, I was trying to emphasis that it is NOT a solution everywhere! there are some on the forums that will take this as an end all solution to energy problems when in fact it is NOT PRACTICAL YET.
Of course it isn't yet (when was something new ever inexpensive), but futurists believe it will be in the near future. Here Ray Kurzweil says in only 20 years time:
Solar Power to Rule in 20 Years, Futurists Say | LiveScience

"We also see an exponential progression in the use of solar energy," he said. "It is doubling now every two years. Doubling every two years means multiplying by 1,000 in 20 years. At that rate we'll meet 100 percent of our energy needs in 20 years."

"You could, for example, create hydrogen or hydrogen-based fuels from the energy produced by solar panels and then use that to create fuel for fuel cells, he said. There are already nano-engineered fuel cells, microscopic in size, that can be scaled up to store huge quantities of energy, he said.

Realize that Ray Kurzweil has already founded companies that have had a large affect on the daily lives of people in modern society. He created the digital music keyboard (changing the music industry), and more importantly, worked on text to speech and voice recognition technology.

As far as locality is concerned, solar panels do not have to be physically located at the location of the power demand. It isn't like that today in regards to energy generators and demand. I don't necessarily believe it will be 100% in 20 years, but 10% of the US power in about 20 years, might be doable.

Last edited by f_m; 06-23-2008 at 11:09 PM..
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